The growth behavior of ultrathin (similar to5 nm) SrRuO3 films prepared by pulsed laser deposition (PLD) on SrTiO3 (001) was investigated particularly as a function of growth temperature mainly using synchrotron X-ray diffraction. At a critical growth temperature (similar to500 degreesC), below which no crystallization occurs, an epitaxial SrRuO3 film starts to grow with a broad distribution of single (110) domain along the film growth direction maintaining the epitaxial relationship of SrRuO3[001]/SrTiO3[100] and SrRuO3[-110]//SrTiO3[010]. Its in-plane and out-of-plane crystal alignments improve sharply when a higher growth temperature of 600 degreesC is applied, presumably due to the more thermal energy supplied to the substrate. However, more increase of the growth temperature to 650 degreesC results in no enhancement of atomic ordering but a rougher surface, suggesting that a careful adjustment in the growth temperature is needed to grow an epitaxially well aligned SrRuO3 film possessing a smooth surface. (C) 2004 Elsevier B.V. All rights reserved.